MFV r323105 (partial): 8300 fix man page issues found by mandoc 1.14.1

illumos/illumos-gate@72d3dbb9ab4481606cb93caca98ba3b3a8eb6ce2
https://github.com/illumos/illumos-gate/commit/72d3dbb9ab4481606cb93caca98ba3b3a8eb6ce2

https://www.illumos.org/issues/8300

Prior to integrating the mdocml update to 1.14.1, fix issues found by
new version, especially the "new sentence, new line" style rule.

FreeBSD note: this revision merges only the changes to the CTF manual
page. The changes to the ZFS pages cannot be applied directly.

Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Toomas Soome <tsoome@me.com>
Approved by: Gordon Ross <gwr@nexenta.com>
Author: Yuri Pankov <yuri.pankov@nexenta.com>

Discussed with: avg
MFC after: 2 weeks